CHARACTERIZATION OF NORMAL AND ALTERED FORMS OF DENTIN

牙本质的微结构和性质是几乎所有 修复性牙科手术。正常牙本质表现出变异 结构和属性与位置有关，但在各种其他 牙本质类型、龋齿冠牙本质和硬化症的改变形式 根部牙本质尤为重要。它们是由至关重要的防御性 与成牙本质细胞改变成分有关的机制， 硬度和渗透性。这些改变形式的牙本质很重要 用于牙本质粘结的衬底。因此牙本质与牙本质的粘附性研究进展 牙本质生理学要求对其基本知识有透彻的了解 微观结构、成分和性能。该项目将延长 正常牙本质早期发展起来的知识和技术 这两种重要的牙本质变体在许多情况下都会遇到 临床情况。 龋病在牙本质中产生多层结构，具有不同程度的 构造亏损、脱矿和超矿化。传统上讲 最深的改变层被称为透明牙本质，因为它改变了 折射指数或硬化牙本质，以反映硬度的增加 由于矿化作用的增加。然而，在某些情况下，透明的 牙本质比正常牙本质柔软。这表明不同的子类 透明牙本质可能是由龋齿引起的，这表明使用 透明和硬化牙本质作为可互换的术语不能 对，是这样。牙根硬化性牙本质的研究要少得多。 被认为是由于宫颈的各种刺激过程而形成的 区域和衰老贯穿整个根部，即使在没有龋齿和 以附加晶体阻塞小管腔为特征 至少在宫颈病变中是耐酸的。更改本条例 肾小管间质牙本质尚未建立。很明显，有 关于这些改变的结构和性质的信息不足 牙本质和它们特定的区域。 需要检验的中心假设是，透明的结构 龋性牙本质和硬化性非龋根性牙本质显示出重要的 与的结构、成分和性能差异 正常牙本质。我们将检验这一假设，并澄清其结构和 这些改变形式的牙本质的性质通过十个特定的行为 AIMS，五个与龋齿有关，五个平行与硬化症有关 颈部和根部牙本质。其中包括绘制改变的牙本质区域图 包括XTM的矿物级、SEM/EDS和AFM的结构、硬度 通过显微硬度和原子力显微镜纳米硬度(目标1，6)。我们还将测试 改变形式的牙本质对不同的反应 脱矿和渗透性变化(目标2，6)。这个 假设管间区的组成和结构 矿物质改变了，而肾小管周围没有改变，将被检测 用显微傅里叶变换红外光谱、原子力显微镜、扫描电子显微镜、扫描电子显微镜和电子显微镜研究龋齿牙本质 绕射和剥离(目标3，4)。将进行类似的研究，以 使用类似方法硬化颈部和根部牙本质(目标8，9)。

Dentin microstructure and properties are determinants of nearly all operations in restorative dentistry. Normal dentin exhibits variation in structure and properties with location, but among the various additional dentin types, the altered forms of carious coronal dentin and sclerotic root dentin are particularly important. They result from vital defensive mechanisms associated with the odonoblasts which alter composition, hardness and permeability. These altered forms of dentin are important substrates for dentin bonding. Thus progress in adhesion to dentin and dentin physiology require a thorough knowledge of their basic microstructure, composition, and properties. This project will extend the knowledge and techniques developed ina th prior period for normal dentin to these two important variations of dentin which are encountered in many clinical situations. Caries produces a multi-layered structure in dentin with varying degrees of structural loss, demineralization and hypermineralization. Traditionally the deepest altered layer is termed transparent dentin, due to its altered refractive index or sclerotic dentin to reflect the increase in hardness due to increased mineralization. However, in some cases, transparent dentin is softer than normal dentin. This suggests that varying subclasses of transparent dentin could result from caries and suggests that the use of transparent and sclerotic dentin as interchangeable terms may not be correct. Sclerotic dentin of the root is much less studied, and is considered to form due to a variety of irritation processes in the cervical region and aging throughout the root, even in the absence of caries and is characterized by occlusion of the tubule lumen with additional crystals that are acid resistant, at least in cervical lesions. Alteration of the intertubular dentin has not been established. it is clear that there is insufficient information on the structure and properties of these altered dentins and their particular zones. The central hypothesis to be tested is that the structure of transparent carious dentin and sclerotic non-carious root dentin exhibit important structural, compositional, and properties differences as compared with normal dentin. We will test this hypothesis and clarify the structure and properties of these altered forms of dentin through conduct of ten specific aims, five related to caries and five parallel aims related to sclerotic cervical and root dentin. These include mapping zones of altered dentin including the mineral level by XTM, structure by SEM/EDS and AFM, hardness by microhardness and AFM nano-hardness (aims 1,6). We also will test the hypothesis that altered forms of dentin respond differently to demineralization and exhibit changes in permeability (aims 2,6). The hypothesis that the composition and structure of the intertubular zone mineral is altered, while the peritubular is not, will be tested for carious dentin using micro-FTIR, AFM, SEM/EDS/WDS and TEM with electron diffraction and PEELS (aims 3,4). Similar studies will be conducted for sclerotic cervical and root dentin using similar methods (aims 8,9).